Flotation cell with radial launders for enhancing froth removal

Abstract

A froth flotation cell comprising a tank and an impeller rotatably disposed in the tank for suspending solids and dispersing air in a pulp phase or slurry in the tank, thereby generating froth from the pulp phase. A plurality of radially oriented launders are placed near the top of the tank and have one end connected to an outer launder adjacent the outer periphery of the tank. A secondary launder, concentric with the outer launder may also be placed near the top of the tank and attached to the second ends of the radial launders. The secondary launder is attached to a dispersing mechanism located around the impeller. The secondary launder is in fluid communication with the radial launders, and the radial launders are likewise in fluid communication with the central launder. This provides a network of launders which collects froth at various locations throughout the flotation cell and causes rapid removal of froth from the flotation cell.

What is claimed is: 
     
       1. A flotation cell for removing mineral values present in a slurry, comprising: a tank for holding a mass of the slurry containing said mineral values;   a mechanism in the tank introducing gas into the slurry and generating froth near the top of the mass of the slurry;   a launder adjacent a periphery of the tank constituting an outer launder, said outer launder removing froth from the tank during operation of the flotation cell;   an inner launder in the tank that is of a size smaller than the outer launder and disposed generally toward the center of the tank said inner launder collecting froth from the tank; and   at least one radial launder in the tank, said radial launder extending from adjacent said outer launder generally inwardly toward an inner portion of said tank, said at least one radial launder receiving froth from the tank and is in fluid flow communication with the outer launder and the inner launder to enhance recovery of froth from the tank.   
     
     
       2. The flotation cell of claim 1, further comprising a plurality of radial launders disposed in the tank. 
     
     
       3. The flotation cell of claim 2, wherein said radial launders are arranged circumferentially equispaced. 
     
     
       4. The flotation cell of claim 1, wherein said outer launder includes an upper lip that defines the level of the froth in the tank. 
     
     
       5. The flotation cell of claim 4, wherein the at least one radial launder includes a lip coplanar with the lip of the outer launder. 
     
     
       6. The flotation cell of claim 1, wherein at least one radial launder discharges the received froth into the outer launder. 
     
     
       7. The flotation cell of claim 1, wherein said radial launder, inner launder, and outer launder each have a, generally coplanar lip defining the level of froth in the tank. 
     
     
       8. The flotation cell of claim 1, wherein the inner launder discharges the froth into the at least one radial launder. 
     
     
       9. The flotation cell of claim 1, further having a device for delivery of wash liquid to at least one of the inner or radial launders to enhance flow of froth through the radial launder. 
     
     
       10. The flotation cell of claim 2, further comprising a device for delivery of wash liquid to at least one of the outer or radial launders to enhance flow of froth through said radial launder. 
     
     
       11. A flotation cell for recovering mineral values contained in a slurry, comprising: a tank for receiving and holding a mass of the slurry;   a mechanism in the tank adjacent the middle of the tank introducing gas and creating froth containing mineral values near top of the slurry mass in the tank;   a launder adjacent a periphery of the tank constituting an outer launder, said outer launder removing froth from the tank during operation of the flotation cell;   an inner launder in the tank, said inner launder substantially surrounding said mechanism, said inner launder receiving froth from the tank and discharging the received froth from the tank to enhance removal of the froth from the tank; and   at least one radial launder in the tank, said radial launder extending from adjacent said outer launder generally inwardly toward an inner portion of said tank, said at least one radial launder receiving froth from the tank and in fluid flow communication with the outer launder and the inner launder to enhance recovery of froth from the tank.   
     
     
       12. The flotation cell of claim 1, further comprising a plurality of generally radially oriented vertical baffles mounted in said tank for reducing angular momentum of said froth while enhancing radial momentum thereof. 
     
     
       13. The flotation cell of claim 1, further comprising at least one opening toward a lower end of said tank for delivery of slurry to said tank. 
     
     
       14. The flotation cell of claim 1, further comprising an impeller mounted for rotation in said tank, with said impeller being positioned generally toward an upper end of said tank and suspending solid particulates in the slurry upon rotation and inducing radial and angular motion of the slurry away from said impeller. 
     
     
       15. The flotation cell of claim 14, wherein said mechanism comprises an upper conduit for delivery of gas to said impeller for dispensing gas bubbles into the slurry to generate a froth of air, liquid and solid particulates that is of lower density than the slurry and thus raises toward the top of said tank. 
     
     
       16. The flotation cell of claim 14, further comprising a dispenser around said impeller and defining together with the inner periphery of said tank a flow channel for flow of the froth from said dispenser up to said outer launder. 
     
     
       17. The flotation cell of claim 1 wherein said at least one radial launder comprises a plurality of radial portions extending from adjacent said tank periphery generally toward the center of said tank. 
     
     
       18. The flotation cell of claim 12, wherein said baffles are mounted in said tank independent of direct attachment to the interior periphery of said tank. 
     
     
       19. The flotation cell of claim 12, wherein said baffles extend to an upper end and generally above a dispenser in said tank and a lower end generally below said disperser. 
     
     
       20. The flotation cell of claim 13, wherein said opening is positioned below a baffle and a impeller. 
     
     
       21. The flotation cell of claim 14, further comprising a draft tube extending from adjacent said lower end tank up to said impeller.